Patent GB-219930-A (GB)
Title: Improvements in or relating to overload-release oil-break switches
IPC: H01H33/02
Filed: 1924-03-06
Abstract: 219,930. Akt.-Ges. f³r Patentverwertung. Aug. 4, 1923, [Convention date]. Automatic circuit-breakers ; oilswitches; cases.-overload-release oilbreak switches have the immersed part of the rigid conductors carrying the fixed contacts utilized for carrying the overload coil and armature, the immersed part being insulated merely by the oil. The casing 1 is covered with insulating material and the upper part 2 is of metal and has apertures cut in its upper face to afford passage to the leads 3, 4. Two insulating supports 7 are secured to grooves 6 cast with the upper part of the switch and carry terminals 8. The left-hand support 7 carries the overload elements comprising an iron bar 9, winding 10, and a toothed armature 11 pivoted to a bracket 13 which carries a spring 15 adjustably secured to the armature 11 by a toothed slide 16. An adjustable pin 18 on each armature passes through a hole 19 in each bar 9 and strikes a strip 21 of insulating material pivoted at 20 and carrying a stud 23 under the release pawl 24. The forked finger piece 25, pivoted to the casing at 26, locks the main pawl 28, pivoted at 29, by means of roller 27. Links 31 are pivoted at 30 and articulated to the switch rod 32 at 33, while plates 35 are pivoted at 34 to the switch rod and to the point 29, so the rod 32 moves parallel to its own axis. The pawl 28 engages with a tendency to release the mechanism the intermediate pawl 36, the tip 37 of which engages a projection on the release pawl 24 under the action of a spring 38 and resists this tendency. The intermediate pawl 36 is released when the pawl 24 is tripped by the stud 23 so the rod 32 drops leaving the pawl 28 unmoved until the load is removed from the finger-piece 25. The load being removed, the finger-piece drops so that the main pawl reengages the intermediate pawl and the switch is ready to be reset. The rod 32 carries brush and sparking contacts engaging contacts 12, 12<1>. The no-volt release comprises the wound core 42 and armature 43 which is pivoted at its top end. On a pin 44 is pivoted a lever 45 having a roller 46 which tends to move the armature 43 away from the core when the lever 45 is raised. A spring- controlled lever 48 is pivoted at 47 to lever 45, a lug on the right-hand end thereof being pressed against lever 45 by a tension spring 49 which is loaded by a pin 50 on the rod 32 when the latter is raised to close the switch. The pin 50 by means of said lug also turns lever 45 upwards and the roller 46 is thus pressed against the armature 43. The armature is released at zero-voltage and the lever 45 and roller 46 can fly upwards, under the action of spring 49 and the action of the lug on the pin 50 rocking the lever 48 about its pivot 47, and thereby operate the pawl 24 to actuate the release pawl 24. Connection may be made by removing the cover 5 and the leads may be inserted in the part 2 of the casing from above or below, the part 2 projecting for this purpose. The supports 7 are removable so that they may be replaced by others carrying new elements and the release mechanism is slender but has a large transmission ratio between contact pressure and releasing force.